Abstract: A new chemical oscillator in group Ⅵ A was first discovered in the Na₂S₂O₈-KSCN-CuSO₄ system.In a batch reactor the reaction displays single-peak behavior in redox potential.In a continous stirring tank reactor(CSTR) the reaction displays sustained oscillations both in redox potential and pH.Depending upon the composition and flow rate of the input stream, we find either a low pH(pH=l~4) steady state,sustained oscillation(pH=5~6) ,or a high pH(pH=9~10)steady state.The reaction system still displays oscillation behavior when the reductant (SCN^-)is in excess.The oscillatory region is very narrow in NaOHconcentration(3×10^-3 mol/L<[NaOH] <1×10^-2 mol/L).

Key words: Chemical oscillation, Nonlinear chemical reaction, Peroxodisulfate, Thiocyanate